Display screen or portion thereof with a graphical user interface



The FIGURE is a front view of a display screen or portion thereof with a graphical user interface showing the new design with environment in broken lines.

In the drawing, the outermost broken line illustrate the display screen or portion thereof and forms no part of the claimed design. The remaining broken lines outside of the solid lines illustrate unclaimed environmental context portions of the graphical user interface and form no part of the claimed design. The broken lines within the solid line bars includes unclaimed text and data values that provide context for the solid line bars, solid line check boxes, and solid line circle circles. These unclaimed text and data values form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface showing the new design, as shown and described. 